A Review of Safety, Health and Environmental (SHE) Issues of Solar Energy System
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Renewable and Sustainable Energy Reviews 41 (2015) 1190–1204 Contents lists available at ScienceDirect Renewable and Sustainable Energy Reviews journal homepage: www.elsevier.com/locate/rser A review of Safety, Health and Environmental (SHE) issues of solar energy system M.M. Aman a,n, K.H. Solangi b, M.S. Hossain c, A. Badarudin b, G.B. Jasmon a, H. Mokhlis a, A.H.A. Bakar c, S.N Kazi b a Department of Electrical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia b Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia c UM Power Energy Dedicated Advanced Centre (UMPEDAC) Level 4, Wisma R&D, University of Malaya, Jalan Pantai Baharu, 59990, Kuala Lumpur, Malaysia article info abstract Article history: Solar energy is one of the cleanest forms of energy sources and considered as a green source of energy. Received 4 April 2014 Solar energy benefit ranges from low carbon emission, no fossil fuel requirement, long term solar Received in revised form resources, less payback time and other. However like other power generation sources, solar energy has 11 August 2014 also some Safety, Health and Environmental (SHE) concerns. This paper presents the overview of solar Accepted 31 August 2014 energy technologies and addresses the SHE impact of solar energy technologies to the sustainability of human activities. This paper will also recommend the possible ways to reduce the effect of potential Keywords: hazards of widespread use of solar energy technologies. Solar energy technology & 2014 Elsevier Ltd. All rights reserved. Photo voltaic Life Cycle Assessment Contents 1. Introduction....................................................................................................... 1191 2. Solar technology . 1192 2.1. Photovoltaic (PV) . 1192 2.2. Concentrating solar power (CSP) . 1193 3. Life Cycle Assessment for harmonization in technology comparison . 1194 3.1. Carbon footprints. 1194 3.2. Energy payback ratio (EPR) . 1194 3.3. Energy payback time (EPT) . 1195 3.4. Life-cycle and land-use (LCLU) . 1195 3.5. Levelized cost of electricity (LCOE) . 1196 4. SolarenergyimpactsonSafety,HealthandEnvironment(SHE)..................................................................1196 4.1. Positive impacts of solar energy . 1197 4.1.1. Saving in natural energy resources . 1197 4.1.2. Water consumption reduction . 1197 4.1.3. Land transformation/land use . 1198 4.1.4. Reduction of carbon dioxide emission . 1198 4.1.5. Noise and visual impacts. 1199 4.2. Negative impacts of solar energy . 1199 4.2.1. Cost of land . 1200 4.2.2. Toxic chemical content in solar panel manufacturing . 1200 4.2.3. Ecological impacts . 1200 4.2.4. Decommissioning and recycling of solar panels. 1201 5. Recommendations for a clean solar industry . 1201 6. Conclusion........................................................................................................1201 n Corresponding author. E-mail address: [email protected] (M.M. Aman). http://dx.doi.org/10.1016/j.rser.2014.08.086 1364-0321/& 2014 Elsevier Ltd. All rights reserved. M.M. Aman et al. / Renewable and Sustainable Energy Reviews 41 (2015) 1190–1204 1191 Acknowledgment . 1201 AppendixA. .......................................................................................................... 1201 References............................................................................................................1202 1. Introduction around 1700 TW and solar has a potential of 6500 TW. However, currently 0.02 TW of wind and 0.008 TW of solar is being utilized Due to current economic reforms and enormous technological [2]. Global environmental concerns and the escalating demand for developments around the world, the energy consumption is energy have also accelerated worldwide attention on green increasing exponentially. In 2011–2012, the energy consumption energy. Solar energy potential is largest among the natural energy was increased by 2.1% and in between 2000 and 2012, the energy resources. Solar energy is obtained from the thermal radiation consumption increase rate was 2.4% [1]. Total world energy use is emitted by the sun. At ground level, solar irradiance is attenuated also expected to rise by 56% in between 2010 and 2040 from 524 by the atmosphere to about 1000 W/m2 in clear sky conditions quadrillion British thermal units (Btu) in 2010 to 820 quadrillion within a few hours of noon – a condition called ‘full sun’. Solar Btu in 2040 [2]. Presently the maximum power consumption energy's potential estimates in the range from 1575 to 49,837 around the world at any given moment is 12.5 TW and it is EJ/year, which is roughly 3–100 times the world's primary energy expected by 2030, the world will require 16.9 TW [3]. According consumption in 2008 [9,10]. Nowadays, about 46 countries are to the International Energy Agency (IEA) statistics, 32.8% of actively promoting solar energy systems. The worldwide solar generation is based on oil, 27.2% based on coal, 20.9% is based on photovoltaic (PV) generation capacity continues to increase and natural gas and the remaining 19.1% based on nuclear, hydro and has become a rapidly growing industry [11]. IEA has estimated the others [4,5]. To fulfill the current projection of 16.9 TW by 2030, future growth of other renewable energy potential as shown in 13,000 large new coal power plants will be needed [2,6]. Heavily Fig. 1. By 2030 it is expected, that the renewable energy will reliance on fossil fuel will also increase the CO2 emission and the contribute 450 billion kWh/year. However solar contribution will largest emission is coming from the electricity sector. In US, be less in comparison to wind and bio-mass due to low efficiency electricity generators consumed 36% of country energy from fossil and other Safety, Health and Environmental issues. IEA has fuels and emitted 41% of the CO2 from fossil fuel combustion in estimated that by 2050, electricity generation from PV will reach 2011. Heavy rely on coal for electricity combustion is also among 4572 TWh (11% of global electricity production) and thus 2.3 Gt of the reason for such high CO2 emission. In 2011, 42% of electricity is CO2 emissions per year will be achieved [12–14]. Here it is also a produced from coal in US and accounted for 95% of coal consumed need to mention that the capacity factor of solar and wind based for energy [7]. power plant is smallest among all renewable and non-renewable The current need is to shift from conventional fossil fuel plants sources. Capacity factor is a measure of how often an electric to mix clean source of energy. The promotion of alternative generator runs for a specific period of time. The capacity factor of environmental friendly fuels can play a vital role to mitigate the solar PV based plant is 0.16, CSP based plant is 0.43 and wind has CO2 emission and favor economic growth. However to cut down only a capacity factor of 0.40 [15]. Thus the efficiency of such the world CO2 emissions from 42 Gt to 39 Gt, the worldwide power plants needs to maximize to get the maximum output. investment in renewable energy sector assets need to be raised Solar energy benefit ranges from low carbon emission, no fossil from $100 billion to $500 billion during 2010–2030 [8]. Thus, in fuel requirement, long term solar resources, less payback time and addition to heavy investment in clean energy services, the power other. However like other power generation sources, solar energy consumption should also be decreased by introducing energy has also some Safety, Health and Environmental (SHE) concerns, efficient devices in the market to sustain the mixed clean energy which needs to be addressed. For example in PV solar cells source. manufacturing, some highly toxic materials like cadmium, lead, Renewable energy and nuclear power are the world's fastest- nickel and other compounds are used, which have been restricted growing energy sources; each of them is increasing by 2.5% per by the global environmental protection agencies [10,16–21]. Use of year [4,5]. Study has shown that, the wind has a total potential of such materials on mass scale is highly unhealthy for the local Fig. 1. Projected non-hydropower renewable electricity generation, 2010–2035 [12]. 1192 M.M. Aman et al. / Renewable and Sustainable Energy Reviews 41 (2015) 1190–1204 habitat. In addition, like other sources of power generation, PV into wafers roughly 0.2 mm thick before the wafers are chemically modules also generate CO2 and other GHG at some stages in their treated and electrical contacts are made. They are cut from single life. Pure silicon metal (Simet) is used in PV panel manufacturing. crystals to become highly efficient. These modules convert up to Simet is produced in electric arc furnaces from quartz reacting at 15% of the energy from the sun into electricity, and test models very high temperatures with reduction elements like coal, coke, over 20% [34]. Polycrystalline (also known as multi-crystalline) charcoal, wood chips and the furnace graphite electrodes. The modules are made from cells containing lots of small silicon basic carbo-thermic reduction reaction for production of Simet is crystals [35]. This makes them the production cost cheaper but stated in Eq. (1). also slightly less efficient than mono-crystalline modules. Many small crystals provide polycrystalline modules a frosted look. SiO2 þ2C-Simet þ2CO ð1Þ While the 0.2 mm wafers in crystalline cells are already incre- The products of the process are silicon alloy, condensed silica dibly thin, the layers making the thin-film modules are of just fumes and recoverable heat energy. Until the last finish product in 2 μm which is about 40 times thinner than a strand human hair solar cell manufacturing, number of chemicals are used and (a micron is one-millionth of a meter). The layers can be deposited different GHG emitted in different chemical processes are elabo- on glass forming a panel similar to the crystalline modules, but rated elsewhere [22–24].